Mercury switch and the like



Marsh 1, 1932. s. HELD 1,847,183

MERCURY swncn AND THE LIKE Filed July 2, 1950 2 Sheets-Shet 1 2 Sheets-Sheer. 2

yyd

S. HELD MERCURY SWITCH AND THE LIKE Filed July 2, 1930 z .H M w 5 a 1 NV ,9. m LE MW w W a e 5 m g 7 224 7 7 7 4 March 1, 1932.

Patented Mar. 1, 1932 UNITED "STATES SIEGFRIECD HELD, OF CHICAGO, ILLINOIS MERCURY SWITCH AND THE LIKE Application filed July 2,

This invention has to dowith certain improvements in mercury switches and the like. The mercury switch construction herein disclosed is especially intended for use in cona nection with the starting and control of such devices as induction motors and the like, although it will presently appear that the switch herein disclosed may also be used for w many other purposes than the foregoing. 19 Nevertheless, inasmuch as the switch herein disclosed has been designed and arranged with particular reference to the needs of such service as the foregoing, I have illustrated i and will describe the foregoing particular application of usefulness of the features of the invention. In so doing, however, I wish it distinctly understood that I do not intend thereby to limit either the usefulness or function of the device except as I may do so in the claims.

lVith the above inmind, I will state that in the starting of electrical devices v su-ch as induction motors, there is encountered a heavy T. rush of current which continues for only a short interval, generally only a few seconds, until the motor attains a speed and operating condition such that this'rush of current stops or becomes greatly abated. Thereafter the A volume of current flow is only of the amount normally necessary for the continued operation of the motor or other machine. Frequently, the initial rush of current amounts to several times the normal full load rated current capacity. a i It is also necessary to provide fuses or other suitable protective devicesfor protecting the circuits against the effects of an excessive current flow under the normal-oper- T ating conditions. These fuses are restricted in capacity to an amount of current flow which is safe for the normal operation of the motor, but the fuses will not carry a current amounting to several times this capacity.

, Consequently, it becomes necessary to make provision for cutting out or shunting these fuses during the starting operation of the motor, after which they must be cut into service when the motor gets under operation so as to v perform their normal protecting function during the operation of themachine.

1930. Serial No. 465,383.

One object of the present'invention is to provide a mercury switch construction which is so arranged that rovision is made for the accommodation of the necessary protecting fuses to protect the circuit in its normal operation; but the switch construction itself is of a two throw or double throw type. W nen thrown into one position the current is delivered directly to the motor or other current consuming terminals, whereas, when the switch is thrown into the other position, the current is compelled to flow through the fuses and thereby protect the circuit in the normal manner.

Another feature of the invention relates to the provision of an arrangement and construction such that it lends itself admirably to use either in connection with single phase circuit connections or poly-phase circuit connections. The latter conditions are accom- 7 plished by mere multiplication of the number of switch cell sections and corresponding fuse section.

' Another feature of the invention relates to the provision of an arrangement such that the protecting fuses are accommodated in individual cells or pockets effectively insulated from each other; but at the same time the arrangement is such that said fuses are readily accessible at all times for inspection or replacement.

Another feature of the invention relates to the provision of a device embodying the foregoing features and which is so formed and arranged that it can be readily produced by moulding or other similar convenient manufacturing operations. This will make it possible to produce the device by moulding operations from bakelite or other similar insulation material, preferably a condensation product of phenol and formaldehyde.

Another feature of the invention relates to the provision, in a switch embodying the above characteristics, of a construction such that the actual. operations of establishing and opening the circuit are performed by the joining together or severance of different portions of a mercury bath as distinguished from a construction in which these results are pro- I duced by the establishment and discontinuance of connection between the mercury and the terminals themselves.

Other objects and uses of the invention will appear from a detailed description of the same which consists in the features of corn struction and combinations of parts hereinafter described and claimed.

In the drawings:

Figure 1 shows a top plan view or? a three phase or three unit device embodying the features of the present invention, a portion of the cover plate being brolzcn away so as to reveal the interior construction in plan view;

Figure 2 shows a vertical section on the line 22 of Figure 1, looking in the direction of the arrows;

Figure 3 shows a bottom view of the device of Figures 1 and 2;

Figure at snows a cross section on the lines l-4e of Figures 1 and 2, looking in the directions of the arrows;

Figure 5 shows a cross section on the lines 5-5 of F igures 1 and 2, looking in the directions of the arrows; and

Figure 6 shows a cross section on the lines 66 of Figures 1 and 2, looking in the directions of the arrows.

In the device illustrated there is included a body member 7 of general pan shape. At its sides this body member is provided with the upwardly extending walls 8 and 9; and it is also provided with the end walls 10 and 11, and the transverse partitions 12 and 13. The side walls 8 and 9, end walls 10 and 11, and partitions 12 and 13, all reach up to substantially the same elevation to receive a comparatively flat cover plate 14 which when set into place seals over and closes the body of the s icture. There produced thereby series of cells 14, 15 and 16, in the present instance three cells, cor 'esponding to the three phases or circuit wires to be controlled.

The body member 7 is also provided with upwardly reaching weirs 17 and 18 in each of the cells, said weirs reaching up only part way so as to subdivide the body member 1 into end pockets l9 and 20, and a central pocket 21 for each of the cells Ll, l5 and 16.

The cover plate 14, conveniently held in place by screws 22 which extend down into bosses 23 formed in the body member 7. Said cover plate also carries the downwardly e1".- tending pins 21. 25, and 26, reaching into the pockets 1901? the three cells 14, 15, and 16, respectively. Said cover plate also carries the downwardly extending pins 27, 28, and 29, reaching down into the pocke s 20 of the three cells 14:, 15, and 16 respectively.

The upper ends of all of these pins carry spring clips 27 which reach up from the cover plate 14. These spring clips are in pairs at the two sides of the cover plate and. they receive the connecting ends of tlr novable fuse elements 28, 29, and 30, respectively for the three phases or branches of the circuit being orotected.

There are contact pins 31, 32, and 33 reaching upwardly into the pockets 21 of the cells let, 15, and 16, respectively. These pins 31., 32 and 33 connect to the incoming power line terminals. There are other pins 3 1 and 35 and 36', reaching upwardly into the pockets 20 of the three cells 1 1-, 15 and 16 rcspcctively. These pins 3%, 35, and connect to the terminals of the motor or other device being controlled. Preferably the upper ends of the pins 3 1, 35, and 36 are provided with cups 37, which receive the lower ends of the pins 27, 28 and 29, with a sui'licient amount of clearance to permit mercury to be trapped or caught in said cups. Consequently, the pins 27, 28 and 29 are electrically connected at all times to the corresponding pins 34, 35, and 36 respectively.

The body member 7 is pivotally mounted upon bosses 38 and 39 about which it can be rocked on a horizontal axis extending across the different cells and preferably said axis is located substantially in line with the floor of the body member 7.

In operation, a sutficient body of metallic mercury or other suitable conducting liquid is placed in each of the cells for the intended operation. This operation will be readily understood from an examination of Figure 2 in particular. When the device is tilted over towards the left, the mercury will extend over the partition 17 so as to establish direct connection between the pockets 19 and 21, as shown by the dotted line 10. This will establish connection, for example, between the incoming terminal 31 of the cell 1! and the pin 2% of said cell, thence across the fuse and down through the pin 27 to the motor terminal pin 34. It will be noted that in this position there is trapped a body of mercury in the pocket 20 indicated by the dotted line 41; out this body of mercury is cut oil" from direct electrical connection with the body of mercury indicated by the line 10.

Upon tilting the device over towards the right, the mercury level will shift to a position such that the principal body of mercury will be indicated by the dotted line 42. there by establishing direct connection between the incoming pin 31 and the outgoing motor pin 34 withoutconnection through the fuse, so that the fuse is cut out of circuit. At the same time there is trapped a body of mercury in the pocket 19 as shown. by the dotted line 43, but the same is cut off from direct connection with the body of mercury designated by the dotted line l2.

It will be noted that in each of the positions referred to above, the ditl'erent pins are at all times in connection with their respective bodies of mercury so that the circuits are not made and broken at those points. On the contrary, the establishment and breaking of the circuits is always performed by connection of the mercury bodies over the partitions 17 or 18 as the case may be. Thus, for example, the passing from the right hand tilted position where the fuses are cut out to the left hand tilted position where the fuses are cut into circuit, the connection between the mercury bodies 40 and 41 is broken over the partition 18, and the connection between the pockets 19 and 21 is established by the joinirg of the mercury bodies over the partition 1 r If desired, partitions such as 44, 45, 46, and 47 may be extended upwards from the cover plate 14 so as to establish compartments for the different fuses. These partitions may be cut away in their central portions as best shown in Figure 2, so that the central portions of the fuses may be readily taken hold of for the operations of inserting and removing the fuses from the clips. At the same time, the clips 27 and the end portions of the fuses are effectively protected from direct cross connection such as would entail short circuits.

Preferably, also, partitions 48, 49, 50, and 51 are extended downwardly from the body member 7 so as to protect the downwardly extending pins from direct connection with each other.

It will be understood that the different downwardly extending terminal pins are intended to be connected to the incoming and outgoing line terminals by suitable flexible connections such as pigtails, so that the necessary freedom of tilting movement is not impaired.

If desired, the different cells may be filled with suitable insulating and quenching liquid above the mercury bath contained therein.

While I have herein shown and described only a certain embodiment of the features of my present invention, still I do not intend to limit myself thereto except as I may do so in the claims.

I claim:

1. In a device of the class described, the combination of a body member of insulating material, open on its top and having a series of longitudinally extending vertical partitions dividing said body member into a series of longitudinally extending upwardly facing compartments, transverse weirs reaching upwardly from. the floor of each compartment part way to subdivide the floor portion of said compartment into three relatively shallow cups, a central contact member located in the lower portion of each of the central cups, an upwardly extending cup-shaped contact member in each of the end cups along one end of the device, a removable cover plate in said device, downwardly extending contact pins carried by said cover plate in position to reach into the end cups at both ends of the member when the cover plate is in position, the pins at one end of the cover plate reaching into the cup shaped contacts at that end of the device, fuse members removably connected to the cover plate and connecting the respective downwardly extending pins together in pairs, and a body of conducting liquid within each of the compartments of the body member, whereby when the device is tilted in one direction the mercury bodiesestablish: connection from the central cups of the body 7 member over the weirs at one end I of the device and establish connection to the liquid and pins in the adjacent end cups, to thereby insure fiow of current through the fuses and whereby when the device is tilted in the other direction the liquid bodies fiow to'the other end of the device and break the liquid connection between the central cups and the end cups aforesaid and establish connection between the central cups and the end cups wherein are. located the cup-shaped contacts, substantially as described.

2. In a device .of the class described, the v combination of a body member of insulating material, a series of vertical longitudinally extending partitions serving to divide the same into a series of longitudinally extending upwardly facing compartments, transverse upwardly extending partitions extending upwardly to subdivide the lower portion of each compartment into a central upwardly facing cup and a pair of end upwardly facing cups, a central contact member in each of the central cups aforesaid, an end contact member in each of the end cups along one side of the device, a removable cover plate for said body member, suitable upwardly extending clips along the end portions of said cover plate adapted to receive fuse members located above the respective compartments of the body members, downwardly extending pins on the cover plate in connection with the clips aforesaidand reaching downwardly into the respective end compartments of the body member when the cover plate is in position thereon, and bodies of conducting liquid located withinthe respective compartments of the body member, substantially as described.

3. In a device of the class described, the combination of a body member of insulating material having a longitudinally extending upwardly facing compartment, transverse partitions reaching upwardly from the floor of said compartment part way to the top thereof and serving to divide the compartment into a central cup and a pair of end cups, a central contact member in the central cup, an end contact member in the end cup, a removable cover plate for the device, downwardly extending contact pins carried by the end portions of said cover plate and reaching downwardly into the end cups of the body member beneath them, a removably protective device carried by the cover plate and normally establishing electrical connection between the said pins, and a suitable body of conducting liquid contained within the compartment, substantially as described.

4. In a device of the class described, the combination of a body member having a longitudinally extending upwardly facing compartment, transverse partitions reaching upwardly from the floor of said compartment to divide the compartment into a central upwardly facing cup and a pair of end upwardly facing cups, all of said cups being in communication with each other along the upper portion of the compartment, a central contact member in the central cup, an end contact member in one of the end cups, a removable cover plate for the device, downwardly depending pins on the end portions of said cover plate reaching into the respective end compartments of the body member when the cover plate is in position, an electrical protective device carried by the cover plate and normally connecting together the downward- 1y extending pins, and adapted to discontinue such connection under overload condi tions, and a suitable body of conducting liquid Within the device, substantially as described.

5. In a device of the class described, the combination of a longitudinally extending chamber including a floor, side Walls, and cover, there being transversely extending partitions reaching upwardly from the floor and serving to divide the compartment into a central cup and end cups, all of said cups communicating with each other in their upper portions, a central contact member in the central cup, an end contact member in one of the end cups, downwardly extending pins on the end portions of the cover aforesaid reaching into the respective end cups, an electrical protective device on the cover normally connecting together the pins aforesaid but adapted to discontinue such connection under overload conditions, and a suitable body of conductingliquid Within the device, substantial- 1y as described.

SIEGFRIED HELD. 

